Effect of 475°C embrittlement on the low cycle fatigue behaviour of lean duplex stainless steels

STRUBBIA, RENATA; SENNOUR, MOHAMED; HEREÑÚ, SILVINA

FATIGUE & FRACTURE OF ENGINEERING MATERIALS & STRUCTURES (PRINT)

WILEY-BLACKWELL PUBLISHING, INC

Lugar: Londres; Año: 2018 vol. 41 p. 473 - 482

8756-758X

Lean duplex stainless steels (LDSSs) with lower nickel and molybdenum areless susceptible to suffer spinodal decomposition than standard duplex stainlesssteels. It is the purpose of this work to study the effect of thermal embrittlementon the low cycle fatigue behaviour of 2 LDSSs with different Creq and Nieq. Thecorrelation between the fatigue behaviour and the dislocation structure isattempted. Transmission electron microscopy was used to observe the dislocationmicrostructure. Additionally, STEM‐EDS technique in conjunction withVickers microhardness measurements was used to characterize the amplitudeof the spinodal decomposition. The results show that the LDSS with lower Creqand Nieq values exhibits improved fatigue properties in the as received and agedconditions. Furthermore, it is important to emphasize that with an adequatevolume fraction of phases in LDSSs, the ageing treatment leads to an increasein strength without causing a great detriment in low cycle fatigue life.